Fichas
SQL
Fichas del conjunto (7)
- 1What does an asterisk (*) do?An asterisk (*) in the select clause denotes “all attributes”
- 2What does DISTINCT do?SQL allows duplicates in relations as well as in query results. To force the elimination of duplicates, insert the keyword DISTINCT after select.
- 3What does ALL do?The keyword ALL specifies that duplicates will not be removed.
- 4What does FROM do?It lists the relations to be scanned when evaluating the whole SELECT expression.
- 5What does AS do?The SQL mechanism for renaming relations and attributes is accomplished through the AS clause:
old-name AS new-name - 6What does % do?The % character matches any substring.
- 7What does _ do?The _ character matches any character.
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- Descripción
- 1 Database Fichas sobre SQL, creado por linneamd el 15/03/2016.
- Creado por
- linneamd
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